An efficient compact, immutable byte string type (both strict and lazy) suitable for binary or 8-bit character data.
The ByteString type represents sequences of bytes or 8-bit characters. It is suitable for high performance use, both in terms of large data quantities, or high speed requirements. The ByteString functions follow the same style as Haskell's ordinary lists, so it is easy to convert code from using String to ByteString.
Two ByteString variants are provided:
* Strict ByteStrings keep the string as a single large array. This makes them convenient for passing data between C and Haskell.
* Lazy ByteStrings use a lazy list of strict chunks which makes it suitable for I/O streaming tasks.
The Char8 modules provide a character-based view of the same underlying ByteString types. This makes it convenient to handle mixed binary and 8-bit character content (which is common in many file formats and network protocols).
The Builder module provides an efficient way to build up ByteStrings in an ad-hoc way by repeated concatenation. This is ideal for fast serialisation or pretty printing.
There is also a ShortByteString type which has a lower memory overhead and can can be converted to or from a ByteString, but supports very few other operations. It is suitable for keeping many short strings in memory.
ByteStrings are not designed for Unicode. For Unicode strings you should use the Text type from the text package.
These modules are intended to be imported qualified, to avoid name clashes with Prelude functions, e.g.
> import qualified Data.ByteString as BS
Version 0.10.4.0

This is the bytestring builder that is debuting in bytestring-0.10.4.0, which should be shipping with GHC 7.8, probably late in 2013. This builder has several nice simplifications and improvements, and more out-of-box functionality than the older blaze-builder.
Note that this package detects which version of bytestring you are compiling against, and if you are compiling against bytestring-0.10.4 or later, will be an empty package.
This package lets the new interface and implementation be used with most older compilers without upgrading bytestring, which can be rather problematic. In conjunction with blaze-builder-0.4 or later, which offers an implementation of blaze-builder in terms of bytestring-builder, this should let most people try the new interface and implementation without causing undue compatibility problems with packages that depend on blaze-builder.
GHC 7.6 did debut an almost identical interface and implementation, but with slightly different module names and organization. Trying to re-export/rename the builder provided with 7.6 did not turn out to be very practical, because this interface includes new functions that rely on Builder internals, which are not exported in 7.6. Furthermore, these module names should be deprecated in 7.10.
Version 0.10.4.0.1

Compute a patch between two ByteStrings which can later be applied to the first to produce the second. This can be used to save bandwidth and disk space when many strings differing by a small number of bytes need to be transmitted or stored.
The underlying implementation is written in C, and can also be found at http://ccodearchive.net/info/bdelta.html.
Currently, a patch does not save any space when two strings differ by more than 1000 bytes. This arbitrary limit serves to keep applications from spiking in memory and CPU usage, as the algorithm uses quadratic space and time with respect to the length of the patch. A better algorithm may be introduced in a future version of bytestring-delta.
Version 0.1.0.1

This library provides a wrapper to mmap(2), allowing files or devices to be lazily loaded into memory as strict or lazy ByteStrings, using the virtual memory subsystem to do on-demand loading.
Version 0.2.2

More compact representation for strict ByteStrings avoiding the overhead and indirection caused by ForeignPtr.
This representation is useful to reduce the incurred memory overhead when operating with many small, long-lived, distinct byte strings (such as keys for containers).
See documentation in Data.ByteString.Plain for more details about this representation.
As an alternative, recent `bytestring` versions provide Data.ByteString.Short which has a similiar overhead but uses unpinned memory instead (and thus requires an additional string data copy in contrast to Data.ByteString.Plain which allows to share the string data with the associated Data.ByteString value).
Version 0.1.0.1

In some cases, it is useful to know how fast a ByteString is being consumed. Typically, this could be to report some measure of progress to a waiting user, but it could also be to perform some form of testing on input / consumption code.
Version 1.0.3

An efficient finite map from (byte)strings to values.
The implementation is based on big-endian patricia trees, like Data.IntMap. We first trie on the elements of Data.ByteString and then trie on the big-endian bit representation of those elements. Patricia trees have efficient algorithms for union and other merging operations, but they're also quick for lookups and insertions.
If you are only interested in being able to associate strings to values, then you may prefer the hashmap package which is faster for those only needing a map-like structure. This package is intended for those who need the extra capabilities that a trie-like structure can offer (e.g., structure sharing to reduce memory costs for highly redundant keys, taking the submap of all keys with a given prefix, contextual mapping, extracting the minimum and maximum keys, etc.)
Version 0.2.3

This is a library of parser combinators, originally written by Koen Claessen. It parses all alternatives in parallel, so it never keeps hold of the beginning of the input string, a common source of space leaks with other parsers. The '(+++)' choice combinator is genuinely commutative; it makes no difference which branch is &quot;shorter&quot;.
Adapted to use Data.ByteString by Gracjan Polak. Designed as a drop-in replacement for Text.ParserCombinators.ReadP.
Version 0.2